This is a city worth going out of your way for: A colorful town hall square with a fountain of lovers kissing under an umbrella...the classical-style University and Art Museum complete with student lock-up (previous detainees were guilty of "aimless wandering in the streets after dark" and, in the case of any misbehaving faculty, "roistering with students")...St. John's church with its hundreds of terracotta statues...Toompea Hill with its Angel and Devil Bridges...what's rumored to be a pagan sacrificial stone...

I'm in Tartu, Estonia's second city (pop. 100,000), in the southeast of the country--Russia is just across Lake Peipsi.

With so much to see, you probably wouldn't think of venturing into Tartu's less historic quarters. But walk up Riia Street, and you'll notice a dark, gray apartment block. During the 1940s and 1950s, this gloomy building served as the southern Estonian headquarters of the NKVD. They later metamorphosed into the KGB, the Soviet Union's feared security service.

Prisoner cells, torture closets, and a chair with stirrups whose awful purpose doesn't bear contemplating. The KGB Cells Exposition is a grim experience, but it gives you an understanding of Estonia's struggle to regain independence. Known as "the Gray House," 15b Riia Street is the country's only original NKVD/KGB site restored to reflect its grisly purpose of interrogation and imprisonment.

The NKVD took over the building in 1940, deporting the owner (Oskar Somermaa) and his family to separate Siberian prison camps. Mr. Somermaa never returned. Between 1940 and 1941, around 10,000 Estonians were sent to the gulags. Conditions were beyond harsh--some 6,000 of them died there.